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Starke S, Kieslich A, Palkowitsch M, Hennings F, G C Troost E, Krause M, Bensberg J, Hahn C, Heinzelmann F, Bäumer C, Lühr A, Timmermann B, Löck S. A deep-learning-based surrogate model for Monte-Carlo simulations of the linear energy transfer in primary brain tumor patients treated with proton-beam radiotherapy. Phys Med Biol 2024; 69:165034. [PMID: 39019053 DOI: 10.1088/1361-6560/ad64b7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 07/17/2024] [Indexed: 07/19/2024]
Abstract
Objective.This study explores the use of neural networks (NNs) as surrogate models for Monte-Carlo (MC) simulations in predicting the dose-averaged linear energy transfer (LETd) of protons in proton-beam therapy based on the planned dose distribution and patient anatomy in the form of computed tomography (CT) images. As LETdis associated with variability in the relative biological effectiveness (RBE) of protons, we also evaluate the implications of using NN predictions for normal tissue complication probability (NTCP) models within a variable-RBE context.Approach.The predictive performance of three-dimensional NN architectures was evaluated using five-fold cross-validation on a cohort of brain tumor patients (n= 151). The best-performing model was identified and externally validated on patients from a different center (n= 107). LETdpredictions were compared to MC-simulated results in clinically relevant regions of interest. We assessed the impact on NTCP models by leveraging LETdpredictions to derive RBE-weighted doses, using the Wedenberg RBE model.Main results.We found NNs based solely on the planned dose distribution, i.e. without additional usage of CT images, can approximate MC-based LETddistributions. Root mean squared errors (RMSE) for the median LETdwithin the brain, brainstem, CTV, chiasm, lacrimal glands (ipsilateral/contralateral) and optic nerves (ipsilateral/contralateral) were 0.36, 0.87, 0.31, 0.73, 0.68, 1.04, 0.69 and 1.24 keV µm-1, respectively. Although model predictions showed statistically significant differences from MC outputs, these did not result in substantial changes in NTCP predictions, with RMSEs of at most 3.2 percentage points.Significance.The ability of NNs to predict LETdbased solely on planned dose distributions suggests a viable alternative to compute-intensive MC simulations in a variable-RBE setting. This is particularly useful in scenarios where MC simulation data are unavailable, facilitating resource-constrained proton therapy treatment planning, retrospective patient data analysis and further investigations on the variability of proton RBE.
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Affiliation(s)
- Sebastian Starke
- Helmholtz-Zentrum Dresden-Rossendorf, Department of Information Services and Computing, Dresden, Germany
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Aaron Kieslich
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
| | - Martina Palkowitsch
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
| | - Fabian Hennings
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
| | - Esther G C Troost
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
- German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany
- National Center for Tumor Diseases Dresden (NTC/UCC), Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
| | - Mechthild Krause
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden, Germany
- German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany
- National Center for Tumor Diseases Dresden (NTC/UCC), Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
- Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
| | - Jona Bensberg
- TU Dortmund University, Department of Physics, Dortmund, Germany
| | - Christian Hahn
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- TU Dortmund University, Department of Physics, Dortmund, Germany
| | - Feline Heinzelmann
- West German Proton Therapy Centre Essen (WPE), University Hospital Essen, Essen, Germany
- Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Christian Bäumer
- TU Dortmund University, Department of Physics, Dortmund, Germany
- West German Proton Therapy Centre Essen (WPE), University Hospital Essen, Essen, Germany
- German Cancer Consortium (DKTK), Essen/Duesseldorf, Germany
| | - Armin Lühr
- Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
- TU Dortmund University, Department of Physics, Dortmund, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen (WPE), University Hospital Essen, Essen, Germany
- Department of Particle Therapy, University Hospital Essen, Essen, Germany
- German Cancer Consortium (DKTK), Essen/Duesseldorf, Germany
| | - Steffen Löck
- OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
- German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany
- National Center for Tumor Diseases Dresden (NTC/UCC), Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany
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Djoumessi Zamo FC, Njeh CF, Colliaux A, Blot-Lafond V, Moyo MN. Patient specific quality assurance of volumetric modulated arc therapy of synchronous bilateral breast cancer. Med Dosim 2023; 49:177-184. [PMID: 38071091 DOI: 10.1016/j.meddos.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/29/2023] [Accepted: 11/05/2023] [Indexed: 08/04/2024]
Abstract
Synchronous bilateral breast cancers (SBBC) present a considerable issue in external beam radiotherapy because of large fields size and large target volumes. Mono-isocentric volumetric modulated arc therapy (VMAT) appears as an appropriate irradiation technique for these types of tumors. The aim of this study was to demonstrate the utility of a 3D DVH pretreatment quality assurance program in VMAT of SBBC cases. Twenty SBBC patients who underwent radiation therapy in our department were retrospectively enrolled in this study. Fifteen patients were treated exclusively to the mammary glands. Five patients benefited from a dose boost on the tumor bed (60Gy). Nine patients were irradiated on the supraclavicular nodes (50Gy). This dose was delivered in 25 fractions and integrated boost was used when appropriate. Depending on the complexity of the treatment plans; 2 or 4 arcs VMAT plans were used in a mono-isocentric technique. The patient specific quality assurance (PSQA) was evaluated using COMPASS measured data, COMPASS reconstructed (CR) and COMPASS computed (CC) dose compared to treatment planning system (TPS) dose. Clinical evaluation was based on DVH metrics for target volumes and organ at risks. The maximum average dose deviation between TPS, CC, and CR was below 3%. The paired t-test between TPS, CC, and CR shows a strong agreement (p < 0.001). The 3DVH dose distribution comparison between TPS and COMPASS were also performed with good gamma score for global analysis. COMPASS was successfully evaluated as a 3DVH pretreatment system for SBBC despite the large fields size and complex target volumes. It allows the verification of the plan in 3D patient anatomy and the evaluation of dose discrepancies.
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Affiliation(s)
- Francis C Djoumessi Zamo
- Medical Physicist, Centre de Radiothérapie Angouleme, Charente, France; Centre de Physique Atomique Moléculaire et Optique, Douala, Cameroon
| | - Christopher F Njeh
- Department of Radiation Oncology, School of Medicine, Indiana University, IN, 46202, USA.
| | - Anthony Colliaux
- Medical Physicist, Centre de Radiothérapie Angouleme, Charente, France
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Bin S, Zhang J, Shen L, Zhang J, Wang Q. Study of the prediction of gamma passing rate in dosimetric verification of intensity-modulated radiotherapy using machine learning models based on plan complexity. Front Oncol 2023; 13:1094927. [PMID: 37546404 PMCID: PMC10401596 DOI: 10.3389/fonc.2023.1094927] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 07/04/2023] [Indexed: 08/08/2023] Open
Abstract
Objective To predict the gamma passing rate (GPR) in dosimetric verification of intensity-modulated radiotherapy (IMRT) using three machine learning models based on plan complexity and find the best prediction model by comparing and evaluating the prediction ability of the regression and classification models of three classical algorithms: artificial neural network (ANN), support vector machine (SVM) and random forest (RF). Materials and methods 269 clinical IMRT plans were chosen retrospectively and the GPRs of a total of 2340 fields by the 2%/2mm standard at the threshold of 10% were collected for dosimetric verification using electronic portal imaging device (EPID). Subsequently, the plan complexity feature values of each field were extracted and calculated, and a total of 6 machine learning models (classification and regression models for three algorithms) were trained to learn the relation between 21 plan complexity features and GPRs. Each model was optimized by tuning the hyperparameters and ten-fold cross validation. Finally, the GPRs predicted by the model were compared with measured values to verify the accuracy of the model, and the evaluation indicators were applied to evaluate each model to find the algorithm with the best prediction performance. Results The RF algorithm had the optimal prediction effect on GPR, and its mean absolute error (MAE) on the test set was 1.81%, root mean squared error (RMSE) was 2.14%, and correlation coefficient (CC) was 0.72; SVM was the second and ANN was the worst. Among the classification models, the RF algorithm also had the optimal prediction performance with the highest area under the curve (AUC) value of 0.80, specificity and sensitivity of 0.80 and 0.68 respectively, followed by SVM and the worst ANN. Conclusion All the three classic algorithms, ANN, SVM, and RF, could realize the prediction and classification of GPR. The RF model based on plan complexity had the optimal prediction performance which could save valuable time for quality control workers to improve quality control efficiency.
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Affiliation(s)
- Shizhen Bin
- Radiotherapy Center, Third Xiangya Hospital of Central South University, Changsha, China
| | - Ji Zhang
- Radiotherapy Center, Third Xiangya Hospital of Central South University, Changsha, China
| | - Luyao Shen
- Radiotherapy Center, The Central Hospital of Shaoyang, Shaoyang, China
| | - Junjun Zhang
- Radiotherapy Center, Third Xiangya Hospital of Central South University, Changsha, China
| | - Qi Wang
- Radiotherapy Center, Third Xiangya Hospital of Central South University, Changsha, China
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Panetta JV, Veltchev I, Price RA, Ma CMC. 2D IMRT QA passing rate dependency on coronal plane. Phys Med 2023; 110:102594. [PMID: 37116388 DOI: 10.1016/j.ejmp.2023.102594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/10/2023] [Accepted: 04/17/2023] [Indexed: 04/30/2023] Open
Abstract
Intensity modulated radiation therapy (IMRT) delivery involves a complex series of beam angles and multileaf collimator (MLC) arrangements, requiring quality assurance to be performed to validate delivery before treatment. The purpose of this work is to investigate the effect of dose gradient on quality assurance (QA) passing rate. Many (n = 40) IMRT plans were delivered and measured using a 2D planar array of ion chambers; additionally, eleven plans were measured at several coronal planes. For each measurement, dose gradient was assessed using a number of metrics and passing rate assessed at both 3%/3 mm and 3%/2 mm criteria. The passing rates of the various IMRT plans were shown to be generally correlated to gradient, with an average distance correlation of 0.54 ± 0.04 for the lateral dose gradient. The passing rate for an individual plan was shown to vary with coronal slice, though the correlation to dose gradient was not predictable. Even though the passing rate was strongly related to dose gradient for many of the plans, the signs of the correlations were not always negative, as hypothesized. The coronal plane at which QA is performed affects passing rate, though dose gradient may not easily be used to predict slices at which passing rate is higher.
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Affiliation(s)
- Joseph V Panetta
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
| | - Iavor Veltchev
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Robert A Price
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - C-M Charlie Ma
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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Putu Inten Gayatri IA, Handika AD, Wibowo WE, Fitriandini A, Fadli M, Yudi Putranto AM, Yudhi Prasada DN, Okselia A, Suharsono, Pawiro SA. 2-Dimensional IMRT dose audit: An Indonesian multicenter study. Appl Radiat Isot 2022; 188:110415. [PMID: 36027871 DOI: 10.1016/j.apradiso.2022.110415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 07/27/2022] [Accepted: 08/09/2022] [Indexed: 11/02/2022]
Abstract
Intensity modulated radiation therapy (IMRT) is an advanced technique in radiation therapy delivery. IMRT depends on the accuracy of the multileaf collimator during treatment. Hence, the actual dose distribution can deviate from the treatment planning system's calculation. This study aimed to perform a multicentre planar dosimetry audit of radiotherapy centres in Indonesia, using the structure sets from AAPM TG-119. The gamma index used to evaluate the dose distribution was 3%/3 mm and 3%/2 mm. We observed 100% gamma index passing rates mostly in the 3%/3 mm evaluations. The gamma index passing rates dropped in the 3%/2 mm analysis. Most of the radiotherapy centres participating in this audit satisfied each criterion's tolerance limit of the action level. This study may become a first result for the next multicenter IMRT audit by using a standardized protocol.
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Affiliation(s)
- Ida Ayu Putu Inten Gayatri
- Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia; Department of Radiation Oncology, MRCCC Siloam Hospitals, Jakarta, Indonesia
| | - Andrian Dede Handika
- Department of Radiation Oncology, Persahabatan General Hospital, Jakarta, Indonesia
| | - Wahyu Edy Wibowo
- Department of Radiation Oncology, Faculty of Medicine, Universitas Indonesia, Cipto Mangunkusumo General Hospital, Jakarta, Indonesia
| | - Aninda Fitriandini
- Department of Radiation Oncology, Faculty of Medicine, Universitas Indonesia, Cipto Mangunkusumo General Hospital, Jakarta, Indonesia
| | - Muhamad Fadli
- Department of Radiation Oncology, MRCCC Siloam Hospitals, Jakarta, Indonesia
| | | | | | - Anisza Okselia
- Department of Radiation Oncology, Hasan Sadikin General Hospital, Bandung, Indonesia
| | - Suharsono
- Department of Radiotherapy, Dharmais National Cancer Center Hospital, Jakarta, Indonesia
| | - Supriyanto Ardjo Pawiro
- Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia.
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Saroj DK, Yadav S, Paliwal N. Does Fluence Smoothing Reduce the Complexity of the Intensity-Modulated Radiation Therapy Treatment Plan? A Dosimetric Analysis. J Med Phys 2022; 47:336-343. [PMID: 36908492 PMCID: PMC9997531 DOI: 10.4103/jmp.jmp_81_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/17/2022] [Accepted: 11/20/2022] [Indexed: 01/11/2023] Open
Abstract
Background Intensity-modulated radiation therapy (IMRT) may have too many peaks and valleys, making the treatment plan undeliverable. When there are too many fluency differences between adjacent pixels in the X or Y directions, the X and Y smoothing factors are utilized as weighting factors to penalize this behavior. Generally, a high degree of complexity is accompanied by many monitor units (MUs), large number of segments, small sized segments, and complex segment shapes. The degree of plan delivery uncertainty can all increase with a higher detailed fluence map. Aim This study aims to evaluate the dosimetric effects of various smoothing levels on the planning target volume (PTV) and organs at risk (OARs) for cervix cancer. Materials and Methods IMRT treatment plans were re-optimized by combining several values of the X and Y penalty between 0 and 100. The dose-volume histogram assessed various dosimetric indicators for PTV and OARs. Additionally, gamma passing rates were evaluated and noted as an indicator of the complex treatment plan. Results At X = 60, Y = 60 fluence map penalty, the conformity index (CI) value reached its highest value of 0.996 ± 0.004. At X = 0, Y = 0, the homogeneity index (HI) was determined to have a maximum value of 0.0628 ± 0.0235. The highest and lowest MU values were 2424.30 ± 471.12 and 1087.80 ± 91.57, respectively, with X = 0, Y = 0 and X = 100, Y = 100. At X = 100, Y = 100, the gamma passing rate reaches its highest value of 99.28% ± 0.44% and minimum value of 85.93% ± 3.87% at X = 0, Y = 0. Conclusion The CI and HI values showed no discernible fluctuation, and the OAR doses were barely affected as smoothing was increased. When the smoothing factor was raised, the number of MUs sharply dropped, and a decrease in the number of segments and higher gamma passing rates were also seen.
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Affiliation(s)
- Dinesh Kumar Saroj
- Department of Radiotherapy, Alexis Multispecialty Hospital, Nagpur, Maharashtra, India
- Department of Physics, Rabindranath Tagore University, Bhopal, Madhya Pradesh, India
| | - Suresh Yadav
- Department of Radiation Oncology, Gandhi Medical College, Bhopal, Madhya Pradesh, India
| | - Neetu Paliwal
- Department of Physics, Rabindranath Tagore University, Bhopal, Madhya Pradesh, India
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Lu W, Li Y, Huang W, Cui H, Zhang H, Yi X. Optimizing the Region for Evaluation of Global Gamma Analysis for Nasopharyngeal Cancer (NPC) Pretreatment IMRT QA by COMPASS: A Retrospective Study. Front Oncol 2022; 12:859415. [PMID: 35774127 PMCID: PMC9238439 DOI: 10.3389/fonc.2022.859415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Background The global gamma passing rate is the most commonly used metric for patient-specific pretreatment quality assurance in radiation therapy. However, the optimal region for evaluation and specific action limits (ALs) need to be explored. Therefore, this study was carried out to explore the optimal region for evaluation of the global gamma passing rate and define ALs by using the COMPASS software. Methods A total of 93 intensity-modulated radiation therapy (IMRT) plans for nasopharyngeal cancer (NPC) patients, including 61 original plans and 32 multileaf collimator (MLC) error-introduced test plans, were selected for retrospective analysis. Firstly, the dose distribution was divided into six isodose regions (“≥10%”, “≥20%”, “≥30%”, “≥40%”, “≥50%”, and “≥60%”) based on the prescribed dose and one clinically oriented region for evaluation (“whole”) to perform the three-dimensional (3D) global gamma reanalysis. Meanwhile, the percentage gamma passing rate (%GP), mean gamma index (μGI) based on 3%/2 mm criteria, and percentage dose error (%DE) of the dose–volume histogram (DVH) metrics were recorded by COMPASS application. Secondly, the Pearson’s correlation coefficient was used to analyze the correlation between %GP and %DE and between μGI and %DE in different regions. Additionally, receiver operating characteristic (ROC) methodology was applied to quantify the fraction of patient-specific plans evaluated as “fail” and “pass”. In order to improve the correlation between gamma analysis result and clinical criteria, ROC analysis was carried out in accordance with hybridization analysis criteria (%DE ≤3%, %GP ≥90% and %DE ≤3%, μGI ≤0.6). ROC was performed for two purposes: 1) to analyze the sensitivity and specificity of %GP and μGI in different regions for evaluation and 2) to define the ALs of %GP and μGI in the optimal region for evaluation. Finally, the plans introduced with MLC errors were prepared for validation. Moreover, we also compared the positive rate of ALs of both %GP and μGI in detecting MLC error-introduced plans in different regions. Results 1) In our study, a number of DVH-based metrics were found to be correlated with the evaluation parameters. The corresponding number was 4, 2, 1, 1, 1, 1, and 3 in γwhole, γ10%, γ20%, γ30%, γ40%, γ50%, and γ60%, respectively, and 5, 3, 0, 1, 1, 4, and 2 in μGIwhole, μGI10%, μGI20%, μGI30%, μGI40%, μGI50%, and μGI60%, respectively. The results by COMPASS have revealed that the %DE of specific structures has a slightly higher correlation with both %GP and μGI of the “whole” region compared with that of any other region. However, it is a moderate correlation (0.5 ≤ |r| < 0.8). 2) The areas under the curves (AUCs) of γwhole, μGIwhole, μGI40%, μGI50%, and μGI60% were >0.7 based on 3%/2 mm criteria. According to the Youden coefficient, we defined the ALs of γwhole ≥92%, μGIwhole ≤0.36, μGI40% ≤0.43, and μGI60% ≤0.40 based on 3%/2 mm criteria. 3) In the validation, for original plans, the accuracy of ALγwhole, ALγ10%, ALμGIwhole, ALμGI40%, ALμGI50%, and ALμGI60% was 23%, 9.8%, 90%, 80.3%, 9.8%, and 88.5%, respectively. For test plans with systematic MLC errors smaller than 0.8 mm, the positive rates of ALγwhole, ALγ10%, ALμGIwhole, ALμGI40%, ALμGI50%, and ALμGI60% were 25%, 58%, 92%, 92%, 42%, and 100%, respectively. For the plans with systematic MLC errors higher than 0.8 mm, the positive rates of all AL%GP and ALμGI were 100%. From the COMPASS validation results, the accuracy of γwhole, μGIwhole, μGI40%, and μGI60% was higher than that of the conventional γ10% and commonly used μGI50%. Conclusions Compared with the traditional evaluation region (i.e., the criteria with a threshold of 10% or a threshold of 50%, it was the same with the isodose regions of “≥10%”, “≥50%” based on the prescribed dose in our study), the “whole” region is more meaningful to the clinic by COMPASS. The accuracy of μGIwhole is higher than that of the conventional γ10% and the commonly used μGI50%.
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Lay LM, Chuang K, Wu Y, Giles W, Adamson J. Virtual patient‐specific QA with DVH‐based metrics. J Appl Clin Med Phys 2022; 23:e13639. [DOI: 10.1002/acm2.13639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/15/2022] [Accepted: 04/25/2022] [Indexed: 12/11/2022] Open
Affiliation(s)
- Lam M. Lay
- Medical Physics Graduate Program Duke University Durham North Carolina USA
| | - Kai‐Cheng Chuang
- Medical Physics Graduate Program Duke Kunshan University Kunshan China
| | - Yuyao Wu
- Medical Physics Graduate Program Duke Kunshan University Kunshan China
| | - William Giles
- Department of Radiation Oncology Duke University Medical Center Durham North Carolina USA
| | - Justus Adamson
- Department of Radiation Oncology Duke University Medical Center Durham North Carolina USA
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Chalise AR, Bojechko C. Using eclipse scripting to fully automate in-vivo image analysis to improve treatment quality and safety. J Appl Clin Med Phys 2022; 23:e13585. [PMID: 35315570 PMCID: PMC9194972 DOI: 10.1002/acm2.13585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/13/2022] [Accepted: 02/23/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE An automated, in-vivo system to detect patient anatomy changes and machine output was developed using novel analysis of in-vivo electronic portal imaging device (EPID) images for every fraction of treatment on a Varian Halcyon. In-vivo approach identifies errors that go undetected by routine quality assurance (QA) to compliment daily machine performance check (MPC), with minimal physicist workload. METHODS Images for all fractions treated on a Halcyon were automatically downloaded and analyzed at the end of treatment day. For image analysis, compared to first fraction, the mean difference of high-dose region of interest is calculated. This metric has shown to predict changes in planning treatment volume (PTV) mean dose. Flags are raised for: (Type-A) treatment fraction whose mean difference exceeds 10%, to protect against large errors, and (Type-B) patients with three consecutive fractions with mean exceeding ±3%, to protect against systematic trends. If a threshold is exceeded, a physicist is e-mailed, a report for flagged patients, for investigation. To track machine output changes, for all patients treated on a day, the average and standard deviations are uploaded to a QA portal, along with the reviewed MPC, ensuring comprehensive QA for the Halcyon. To guide clinical implementation, a retrospective study from November 2017 till December 2020 was conducted, which grouped errors by treatment site. This framework has been used prospectively since January 2021. RESULTS From retrospective data of 1633 patients (35 759 fractions), no Type-A errors were found and only 45 patients (2.76%) had Type-B errors. These Type-B deviations were due to head-and-neck weight loss. For 6 months of prospective use (345 patients), 13 patients (3.7%) had Type-B errors and no Type-A errors. CONCLUSIONS This automated system protects against errors that can occur in vivo to provide a more comprehensive QA. This fully automated framework can be implemented in other centers with a Halcyon, requiring a desktop computer and analysis scripts.
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Affiliation(s)
- Ananta Raj Chalise
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California, USA
| | - Casey Bojechko
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California, USA
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Qiu J, Zhang S, Lv B, Zheng X. Cardiac Dose Control and Optimization Strategy for Left Breast Cancer Radiotherapy With Non-Uniform VMAT Technology. Technol Cancer Res Treat 2021; 20:15330338211053752. [PMID: 34806481 PMCID: PMC8606722 DOI: 10.1177/15330338211053752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Purpose: A novel in-house technology "Non-Uniform VMAT (NU-VMAT)" was developed for automated cardiac dose reduction and treatment planning optimization in the left breast radiotherapy. Methods: The NU-VMAT model based on IGM (gantry MLC Movement coefficient index) was established to optimize the volumetric modulated arc therapy (VMAT) MLC movement and modulation intensity in certain gantry angles. The ESAPI embedded in Eclipse® was employed to connect TPS and the optimization program via I/O relevant DICOM RT files. The adjuvant whole-breast radiotherapy of 14 patients with left breast cancer was replanned using our NU-VMAT technology in comparison with VMAT and IMRT technology. Dosimetric parameters including D1%, D99%, and Dmean of PTV, V5, V10, and V20 of ipisilateral lung, V5, D20, D30, and Dmean of heart, monitor units (MUs), and delivery time derived from IMRT, VMAT, and NU-VMAT plans were evaluated for plan quality and delivery efficiency. The quality assurance (QA) was conducted using both point-dose and planar-dose measurements for all treatment plans. Results: The IGM-NU-VMAT curves with plan optimization (range from 50% to 147%) were converged more significantly than IGM-VMAT curves (range from 0% to 297%). The dose distribution requirements of the target and normal tissues could be met using IMRT, VMAT, or NU-VMAT; the lowest Dmean was achieved in NU-VMAT plans (5.38 ± 0.46 Gy vs 5.63 ± 0.61 Gy in IMRT and 7.95 ± 0.52 Gy in VMAT plans). Statistically significant differences were found in terms of delivery time and MU when comparing IMRT with VMAT and NU-VMAT plans (P < .05). In comparison with IMRT plans, the MU and delivery time in NU-VMAT plans dramatically decreased by 69.8% and 28.4%, respectively. Moreover, NU-VMAT plans showed a high gamma passing rate (96.5% ± 1.11) in plane dose verification and minimal dose difference (2.4% ± 0.19) in point absolute dose verification. Conclusion: Our non-uniform VMAT facilitated the treatment strategy optimization for left breast cancer radiotherapy with dosimetric advantage in cardiac dose reduction and delivery efficiency in comparison with the conventional VMAT and IMRT.
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Affiliation(s)
- Jianjian Qiu
- Huadong Hospital, Fudan University, Shanghai, China
| | - Shujun Zhang
- Huadong Hospital, Fudan University, Shanghai, China
| | - Bo Lv
- Huadong Hospital, Fudan University, Shanghai, China
| | - Xiangpeng Zheng
- Huadong Hospital, Fudan University, Shanghai, China
- Xiangpeng Zheng, MD, Department of Radiation Oncology, Huadong Hospital, Fudan University, 221 West Yan’an Road, Shanghai 200040, China.
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Three-dimensional IMRT QA of Monte Carlo and full scatter convolution algorithms based on 3D film dosimetry. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109528] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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12
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Chan GH, Chin LCL, Abdellatif A, Bissonnette JP, Buckley L, Comsa D, Granville D, King J, Rapley PL, Vandermeer A. Survey of patient-specific quality assurance practice for IMRT and VMAT. J Appl Clin Med Phys 2021; 22:155-164. [PMID: 34145732 PMCID: PMC8292698 DOI: 10.1002/acm2.13294] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/03/2021] [Accepted: 05/06/2021] [Indexed: 12/03/2022] Open
Abstract
A first‐time survey across 15 cancer centers in Ontario, Canada, on the current practice of patient‐specific quality assurance (PSQA) for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) delivery was conducted. The objectives were to assess the current state of PSQA practice, identify areas for potential improvement, and facilitate the continued improvement in standardization, consistency, efficacy, and efficiency of PSQA regionally. The survey asked 40 questions related to PSQA practice for IMRT/VMAT delivery. The questions addressed PSQA policy and procedure, delivery log evaluation, instrumentation, measurement setup and methodology, data analysis and interpretation, documentation, process, failure modes, and feedback. The focus of this survey was on PSQA activities related to routine IMRT/VMAT treatments on conventional linacs, including stereotactic body radiation therapy but excluding stereotactic radiosurgery. The participating centers were instructed to submit answers that reflected the collective view or opinion of their department and represented the most typical process practiced. The results of the survey provided a snapshot of the current state of PSQA practice in Ontario and demonstrated considerable variations in the practice. A large majority (80%) of centers performed PSQA measurements on all VMAT plans. Most employed pseudo‐3D array detectors with a true composite (TC) geometry. No standard approach was found for stopping or reducing frequency of measurements. The sole use of delivery log evaluation was not widely implemented, though most centers expressed interest in adopting this technology. All used the Gamma evaluation method for analyzing PSQA measurements; however, no universal approach was reported on how Gamma evaluation and pass determination criteria were determined. All or some PSQA results were reviewed regularly in two‐thirds of the centers. Planning related issues were considered the most frequent source for PSQA failures (40%), whereas the most frequent course of action for a failed PSQA was to review the result and decide whether to proceed to treatment.
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Affiliation(s)
- Gordon H Chan
- Department of Medical Physics, Juravinski Cancer Centre, Hamilton, Ontario, Canada
| | - Lee C L Chin
- Department of Medical Physics, Odette Cancer Centre, Toronto, Ontario, Canada
| | - Ady Abdellatif
- Department of Medical Physics, R.S. McLaughlin Durham Regional Cancer Centre, Oshawa, Ontario, Canada
| | - Jean-Pierre Bissonnette
- Department of Medical Physics, Princess Margaret Cancer Centre-UHN, Toronto, Ontario, Canada
| | - Lesley Buckley
- Department of Medical Physics, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Daria Comsa
- Radiation Physics Department, Southlake Regional Cancer Centre, Newmarket, Ontario, Canada
| | - Dal Granville
- Department of Medical Physics, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Jenna King
- Radiation Oncology Physics, Simcoe Muskoka Regional Cancer Centre, Barrie, Ontario, Canada
| | - Patrick L Rapley
- Medical Physics Department, Thunder Bay Regional Health Sciences Centre, Thunder Bay, Ontario, Canada
| | - Aaron Vandermeer
- Department of Medical Physics, R.S. McLaughlin Durham Regional Cancer Centre, Oshawa, Ontario, Canada
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Srivastava RP, Basta K, De Gersem W, De Wagter C. A comparative analysis of Acuros XB and the analytical anisotropic algorithm for volumetric modulation arc therapy. REPORTS OF PRACTICAL ONCOLOGY AND RADIOTHERAPY : JOURNAL OF GREATPOLAND CANCER CENTER IN POZNAN AND POLISH SOCIETY OF RADIATION ONCOLOGY 2021; 26:481-488. [PMID: 34277105 PMCID: PMC8281916 DOI: 10.5603/rpor.a2021.0050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/23/2021] [Indexed: 11/25/2022]
Abstract
Background This study aimed to verify the dosimetric impact of Acuros XB (AXB) (AXB, Varian Medical Systems Palo Alto CA, USA), a two model-based algorithm, in comparison with Anisotropic Analytical Algorithm (AAA ) calculations for prostate, head and neck and lung cancer treatment by volumetric modulated arc therapy (VMAT ), without primary modification to AA. At present, the well-known and validated AA algorithm is clinically used in our department for VMAT treatments of different pathologies. AXB could replace it without extra measurements. The treatment result and accuracy of the dose delivered depend on the dose calculation algorithm. Materials and method Ninety-five complex VMAT plans for different pathologies were generated using the Eclipse version 15.0.4 treatment planning system (TPS). The dose distributions were calculated using AA and AXB (dose-to-water, AXBw and dose-to-medium, AXBm), with the same plan parameters for all VMAT plans. The dosimetric parameters were calculated for each planning target volume (PTV) and involved organs at risk (OA R). The patient specific quality assurance of all VMAT plans has been verified by Octavius®-4D phantom for different algorithms. Results The relative differences among AA, AXBw and AXBm, with respect to prostate, head and neck were less than 1% for PTV D95%. However, PTV D95% calculated by AA tended to be overestimated, with a relative dose difference of 3.23% in the case of lung treatment. The absolute mean values of the relative differences were 1.1 ± 1.2% and 2.0 ± 1.2%, when comparing between AXBw and AA, AXBm and AA, respectively. The gamma pass rate was observed to exceed 97.4% and 99.4% for the measured and calculated doses in most cases of the volumetric 3D analysis for AA and AXBm, respectively. Conclusion This study suggests that the dose calculated to medium using AXBm algorithm is better than AAA and it could be used clinically. Switching the dose calculation algorithm from AA to AXB does not require extra measurements.
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Affiliation(s)
- Raju P Srivastava
- Radiotherapy Association Meuse Picardie, Centre Hospitalier Mouscron, Mouscron, Belgium.,Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium
| | - K Basta
- Radiotherapy Association Meuse Picardie, Centre Hospitalier Mouscron, Mouscron, Belgium
| | - Werner De Gersem
- Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium.,Department of Radiation Oncology and Experimental Cancer Research, Ghent University, Belgium
| | - Carlos De Wagter
- Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium.,Department of Radiation Oncology and Experimental Cancer Research, Ghent University, Belgium
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Improving intensity-modulated radiation therapy quality assurance by adopting statistical process control. Cancer Radiother 2021; 26:427-432. [PMID: 34090790 DOI: 10.1016/j.canrad.2021.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/29/2021] [Accepted: 05/09/2021] [Indexed: 11/23/2022]
Abstract
PURPOSE To use statistical process control for intensity-modulated radiation therapy (IMRT) quality assurance (QA) and improve tolerance limits and action limits. METHODS An electronic portal imaging device (EPID) was selected to verify IMRT QA. The I-chart and the exponentially weighted moving averages (EWMA) chart were used to analyze the corresponding results. RESULTS Twenty samples were used to enable the sampling requirements for building the control limits to be met. The I-chart showed that isolated data points beyond the control limits were mainly derived from complex plans. The EWMA made predictions of systematic errors earlier than the I-chart. Systematic errors primarily originated from the dose calibration on the EPID, and recalibrating the EPID could eliminate such errors. CONCLUSION Statistical process control is an effective tool to detect controllable and can be used in IMRT QA. After calibrating the EPID, the tolerance and action limits all improved and satisfied the requirements/recommended values of the AAPM TG-218 report.
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15
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Alwakeel AF, Al Musawi MS, Alabedi HH, Mohammed HJ. Dosimetric assessment of IMRT treatment planning for unilateral breast cancer patient using Octavius phantom detector. APPLIED NANOSCIENCE 2021. [DOI: 10.1007/s13204-021-01836-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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16
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Badali DS, Vainer Y, Ellenor CW, Mitchell CR, Fishman K, Soro N, Price R, Funk T. Inverse treatment planning for an electronic brachytherapy system delivering anisotropic radiation therapy. Phys Med Biol 2021; 66:055004. [PMID: 33429370 DOI: 10.1088/1361-6560/abda9a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An inverse radiation treatment planning algorithm for Sensus Healthcare's SculpturaTM electronic brachytherapy system has been designed. The algorithm makes use of simulated annealing to optimize the conformation number (CN) of the treatment plan. The highly anisotropic dose distributions produced by the SculpturaTM x-ray source empower the inverse treatment planning algorithm to achieve highly conformal treatment plans for a wide range of prescribed planning target volumes. Over a set of 10 datasets the algorithm achieved an average CN of 0.79 ± 0.08 and an average gamma passing rate of 0.90 ± 0.10 at 5%/5 mm. A regularization term that encouraged short treatment plans was used, and it was found that the total treatment time could be reduced by 20% with only a nominal reduction in the CN and gamma passing rate. It was also found that downsampling the voxelized volume (from 3203 to 643 voxels) prior to optimization resulted in a 150× speedup in the optimization time (from 2 + minutes to < 1 s) without affecting the quality of the treatment plan.
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17
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Liu C, Zheng D, Bradley JA, Vega RBM, Li Z, Mendenhall NP, Liang X. Patient-specific quality assurance and plan dose errors on breast intensity-modulated proton therapy. Phys Med 2020; 77:84-91. [PMID: 32799050 DOI: 10.1016/j.ejmp.2020.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/26/2020] [Accepted: 08/05/2020] [Indexed: 01/28/2023] Open
Abstract
PURPOSE To investigate, in proton therapy, whether the Gamma passing rate (GPR) is related to the patient dose error and whether MU scaling can improve dose accuracy. METHODS Among 20 consecutively treated breast patients selected for analysis, two IMPT plans were retrospectively generated: (1) the pencil-beam (PB) plan and (2) the Monte Carlo (MC) plan. Patient-specific QA was performed. A 3%/3-mm Gamma analysis was conducted to compare the TPS-calculated PB algorithm dose distribution with the measured 2D dose. Dose errors were compared between the plans that passed the Gamma testing and those that failed. The MU was then scaled to obtain a better GPR. MU-scaled PB plan dose errors were compared to the original PB plan. RESULTS Of the 20 PB plans, 8 were passed Gamma testing (G_pass_group) and 12 failed (G_fail_group). Surprisingly, the G_pass_group had a greater dose error than the G_fail_group. The median (range) of the PTV DVH RMSE and PTV ΔDmean were 1.36 (1.00-1.91) Gy vs 1.18 (1.02-1.80) Gy and 1.23 (0.92-1.71) Gy vs 1.10 (0.87-1.49) Gy for the G_pass_group and the G_fail_group, respectively. MU scaling reduced overall dose error. However, for PTV D99 and D95, MU scaling worsened some cases. CONCLUSION For breast IMPT, the PB plans that passed the Gamma testing did not show smaller dose errors compared to the plans that failed. For individual plans, the MU scaling technique leads to overall smaller dose errors. However, we do not suggest use of the MU scaling technique to replace the MC plans when the MC algorithm is available.
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Affiliation(s)
- Chunbo Liu
- Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, FL, USA; School of Physical Sciences, University of Science and Technology of China, Hefei, China
| | - Dandan Zheng
- Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Julie A Bradley
- Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, FL, USA
| | - Raymond B Mailhot Vega
- Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, FL, USA
| | - Zuofeng Li
- Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, FL, USA
| | - Nancy P Mendenhall
- Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, FL, USA
| | - Xiaoying Liang
- Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, FL, USA.
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Ghareeb F, Esposito A, Lencart J, Santos JA. Localized extra focal dose collimator angle dependence during VMAT: An out-of-field Monte Carlo study using PRIMO software. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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19
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Yi X, Lu WL, Dang J, Huang W, Cui HX, Wu WC, Li Y, Jiang QF. A comprehensive and clinical-oriented evaluation criteria based on DVH information and gamma passing rates analysis for IMRT plan 3D verification. J Appl Clin Med Phys 2020; 21:47-55. [PMID: 32436351 PMCID: PMC7484885 DOI: 10.1002/acm2.12910] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/28/2019] [Accepted: 04/21/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose To accomplish the 3D dose verification to IMRT plan by incorporating DVH information and gamma passing rates (GPs) (DVH_GPs) so as to better correlate the patient‐specific quality assurance (QA) results with clinically relevant metrics. Materials and methods DVH_GPs analysis was performed to specific structures of 51 intensity‐modulated radiotherapy (IMRT) treatment plans (17 plans each for oropharyngeal neoplasm, esophageal neoplasm, and cervical neoplasm) with Delta4 3D dose verification system. Based on the DVH action levels of 5% and GPs action levels of 90% (3%/2 mm), the evaluation results of DVH_GPs analysis were categorized into four regions as follows: the true positive (TP) (%DE> 5%, GPs < 90%), the false positive (FP) (%DE ≤ 5%, GPs < 90%), the false negative (FN) (%DE> 5%, GPs ≥ 90%), and the true negative (TN) (%DE ≤ 5%, GPs ≥ 90%). Considering the actual situation, the final patient‐specific QA determination was made based on the DVH_GPs evaluation results. In order to exclude the impact of Delta4 phantom on the DVH_GPs evaluation results, 5 cm phantom shift verification was carried out to structures with abnormal results (femoral heads, lung, heart). Results In DVH_GPs evaluation, 58 cases with FN, 5 cases with FP, and 2 cases with TP were observed. After the phantom shift verification, the extremely abnormal FN of both lung (%DE = 21.52%±8.20%) and heart (%DE = 19.76%) in the oropharyngeal neoplasm plans and of the bilateral formal heads (%DE = 26.41%±13.45%) in cervical neoplasm plans disappeared dramatically. DVH_GPs analysis was performed to all evaluation results in combination with clinical treatment criteria. Finally, only one TP case from the oropharyngeal neoplasm plans and one FN case from the esophageal neoplasm plans did not meet the treatment requirements, so they needed to be replanned. Conclusion The proposed DVH_GPs evaluation method first make up the deficiency of conventional gamma analysis regarding intensity information and space information. Moreover, it improves the correlation between the patient‐specific QA results and clinically relevant metrics. Finally, it can distinguish the TP, TN, FP, and FN in the evaluation results. They are affected by many factors such as the action levels of DVH and GPs, the feature of the specific structure, the QA device, etc. Therefore, medical physicist should make final patient‐specific QA decision not only by taking into account the information of DVH and GPs, but also the practical situation.
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Affiliation(s)
- Xin Yi
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wen-Li Lu
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jun Dang
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Huang
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hai-Xia Cui
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wan-Chun Wu
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ying Li
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qing-Feng Jiang
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Sun Y, Zhou G, Zhu Y, Zou L, Tian Y. Appropriate reduction of the fragmentation level of subfield sequences to improve the accuracy of field delivery in IMRT for nasopharyngeal carcinoma. Br J Radiol 2020; 93:20190767. [PMID: 32026724 PMCID: PMC7217578 DOI: 10.1259/bjr.20190767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objective: Due to the influence of gravity, inertia and friction, there will be deviation between the position of multileaf collimator (MLC) in the delivered field and the initial intensity modulated radiotherapy (IMRT) plan. This study explores the effects of the fragmentation level of subfield sequences on this deviation and seeks ways to improve the accuracy of field delivery in IMRT for nasopharyngeal carcinoma (NPC). Methods: 30 patients with NPC were selected, and two groups (groups A and B) of IMRT plans were made in Pinnacle planning system. Different planning parameters were used for optimization so that the subfield sequence fragmentation level of Group B was significantly lower than that of Group A. With the MapCheck2, verification plan was implemented in two ways: 0o gantry angle and the actual treatment angle, then the differences between the two verification results of each group plan were analyzed. Results: The γ-passing rate verified at the actual treatment angle was lower than that of 0o gantry angle for each group plan, whereas the Group B plan shows small reduction. Mean change value (Δ) was decreased from 1.01% (Group A) to 0.40% (Group B) with 3%/3 mm criteria and 2.88% (Group A) to 1.52% (Group B) with 2%/2 mm criteria, respectively. The smaller the difference (Δ), the actual output dose of the field is more consistent with the original plan. There was no significant correlation between this change and the angle of the field. Conclusion: Appropriately reducing the fragmentation level of subfield sequence can reduce the effect of field angle on MLC position and improve the delivery accuracy of IMRT plan. Advances in knowledge: The fragmentation level of the subfield sequence may have an impact on the accuracy of the delivery of the plan. This study demonstrates this assumption by comparing the differences between 0° and actual angle verification. Mean change value (Δ) was decreased from Group A to Group B. The smaller the difference (Δ), the actual output dose of the field is more consistent with the original plan. The result of this study may help us to understand that appropriately increasing the subfield area and reducing the fragmentation level of the subfield sequence can reduce the difference between the two verification results, which can further improve the accuracy of the plan delivery in IMRT and tumor treatment.
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Affiliation(s)
- Yanze Sun
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou, China.,Institute of Radiotherapy and Oncology, Soochow University, Suzhou, China
| | - Gang Zhou
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou, China.,Institute of Radiotherapy and Oncology, Soochow University, Suzhou, China
| | - Yaqun Zhu
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou, China.,Institute of Radiotherapy and Oncology, Soochow University, Suzhou, China
| | - Li Zou
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou, China.,Institute of Radiotherapy and Oncology, Soochow University, Suzhou, China
| | - Ye Tian
- Department of Radiotherapy and Oncology, The Second Affiliated Hospital of Soochow University, Suzhou, China.,Institute of Radiotherapy and Oncology, Soochow University, Suzhou, China
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Mehrens H, Taylor P, Followill DS, Kry SF. Survey results of 3D-CRT and IMRT quality assurance practice. J Appl Clin Med Phys 2020; 21:70-76. [PMID: 32351006 PMCID: PMC7386182 DOI: 10.1002/acm2.12885] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 03/03/2020] [Accepted: 03/17/2020] [Indexed: 01/09/2023] Open
Abstract
PURPOSE To create a snapshot of common practices for 3D-CRT and intensity-modulated radiation therapy (IMRT) QA through a large-scale survey and compare to TG-218 recommendations. METHODS A survey of 3D-CRT and IMRT QA was constructed at and distributed by the IROC-Houston QA center to all institutions monitored by IROC (n = 2,861). The first part of the survey asked about methods to check dose delivery for 3D-CRT. The bulk of the survey focused on IMRT QA, inquiring about treatment modalities, standard tools used to verify planned dose, how assessment of agreement is calculated and the comparison criteria used, and the strategies taken if QA fails. RESULTS The most common tools for dose verification were a 2D diode array (52.8%), point(s) measurement (39.0%), EPID (27.4%), and 2D ion chamber array (23.9%). When IMRT QA failed, the highest average rank strategy utilized was to remeasure with the same setup, which had an average position ranking of 1.1 with 90.4% of facilities employing this strategy. The second highest average ranked strategy was to move to a new calculation point and remeasure (54.9%); this had an average ranking of 2.1. CONCLUSION The survey provided a snapshot of the current state of dose verification for IMRT radiotherapy. The results showed variability in approaches and that work is still needed to unify and tighten criteria in the medical physics community, especially in reference to TG-218's recommendations.
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Affiliation(s)
- Hunter Mehrens
- Imaging and Radiation Core Houston QA Center, Houston, TX, USA.,Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA
| | - Paige Taylor
- Imaging and Radiation Core Houston QA Center, Houston, TX, USA.,Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA
| | - David S Followill
- Imaging and Radiation Core Houston QA Center, Houston, TX, USA.,Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA
| | - Stephen F Kry
- Imaging and Radiation Core Houston QA Center, Houston, TX, USA.,Department of Radiation Physics, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA
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Method to quickly and accurately calculate absorbed dose from therapeutic and stray photon exposures throughout the entire body in individual patients. Med Phys 2020; 47:2254-2266. [DOI: 10.1002/mp.14018] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/11/2019] [Accepted: 12/24/2019] [Indexed: 01/26/2023] Open
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Xia Y, Adamson J, Zlateva Y, Giles W. Application of TG-218 action limits to SRS and SBRT pre-treatment patient specific QA. JOURNAL OF RADIOSURGERY AND SBRT 2020; 7:135-147. [PMID: 33282467 PMCID: PMC7717087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 06/25/2020] [Indexed: 06/12/2023]
Abstract
AAPM TG-218 provides recommendations for standard IMRT pre-treatment QA without giving specifics for stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). In light of this, our purpose is to report our experience with applying TG-218 recommendations to a large multicenter clinical SRS and SBRT program for a range of diverse clinical pre-treatment QA systems. Pre-treatment QA systems included Delta4 (Scandidos), Portal Dosimetry (Varian Medical Systems), ArcCHECK (SunNuclear), and SRS MapCHECK (SunNuclear). Plans were stratified by technique for each QA system, and included intracranial and extracranial IMRT and VMAT (total QA cases n=275). Gamma analysis was re-analyzed with spatial/dose criteria combinations ranging from 1 to 3 mm and 1% to 4%, and action and tolerance limits were calculated per plan type and compared to the "universal" TG-218 action limit of 90%. The analysis indicated that spatial tolerance criteria could be tightened to 1 mm while still maintaining an in-control QA process for all QA systems evaluated.
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Affiliation(s)
- Yuqing Xia
- Medical Physics Graduate Program, Duke Kunshan University, Kunshan, China 215316
| | - Justus Adamson
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27708, USA
| | - Yana Zlateva
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27708, USA
| | - Will Giles
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27708, USA
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Medical physics aspects of Intensity-Modulated Radiotherapy practice in Malaysia. Phys Med 2019; 67:34-39. [DOI: 10.1016/j.ejmp.2019.10.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/05/2019] [Accepted: 10/07/2019] [Indexed: 12/25/2022] Open
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Yu L, Tang TLS, Cassim N, Livingstone A, Cassidy D, Kairn T, Crowe SB. Analysis of dose comparison techniques for patient-specific quality assurance in radiation therapy. J Appl Clin Med Phys 2019; 20:189-198. [PMID: 31613053 PMCID: PMC6839377 DOI: 10.1002/acm2.12726] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 08/08/2019] [Accepted: 08/22/2019] [Indexed: 11/15/2022] Open
Abstract
Purpose Gamma evaluation is the most commonly used technique for comparison of dose distributions for patient‐specific pretreatment quality assurance in radiation therapy. Alternative dose comparison techniques have been developed but not widely implemented. This study aimed to compare and evaluate the performance of several previously published alternatives to the gamma evaluation technique, by systematically evaluating a large number of patient‐specific quality assurance results. Methods The agreement indices (or pass rates) for global and local gamma evaluation, maximum allowed dose difference (MADD) and divide and conquer (D&C) techniques were calculated using a selection of acceptance criteria for 429 patient‐specific pretreatment quality assurance measurements. Regression analysis was used to quantify the similarity of behavior of each technique, to determine whether possible variations in sensitivity might be present. Results The results demonstrated that the behavior of D&C gamma analysis and MADD box analysis differs from any other dose comparison techniques, whereas MADD gamma analysis exhibits similar performance to the standard global gamma analysis. Local gamma analysis had the least variation in behavior with criteria selection. Agreement indices calculated for 2%/2 mm and 2%/3 mm, and 3%/2 mm and 3%/3 mm were correlated for most comparison techniques. Conclusion Radiation oncology treatment centers looking to compare between different dose comparison techniques, criteria or lower dose thresholds may apply the results of this study to estimate the expected change in calculated agreement indices and possible variation in sensitivity to delivery dose errors.
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Affiliation(s)
- Liting Yu
- Royal Brisbane and Women's Hospital, Herston, Qld., Australia.,Queensland University of Technology, Brisbane, Qld., Australia
| | - Timothy L S Tang
- Queensland University of Technology, Brisbane, Qld., Australia.,Beacon International Specialist Centre, Petaling Jaya, Malaysia
| | - Naasiha Cassim
- Royal Brisbane and Women's Hospital, Herston, Qld., Australia
| | | | - Darren Cassidy
- Royal Brisbane and Women's Hospital, Herston, Qld., Australia
| | - Tanya Kairn
- Royal Brisbane and Women's Hospital, Herston, Qld., Australia.,Queensland University of Technology, Brisbane, Qld., Australia
| | - Scott B Crowe
- Royal Brisbane and Women's Hospital, Herston, Qld., Australia.,Queensland University of Technology, Brisbane, Qld., Australia
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A national survey on technology and quality assurance for stereotactic body radiation therapy. Phys Med 2019; 65:6-14. [DOI: 10.1016/j.ejmp.2019.07.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022] Open
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Puzhakkal N, Kochunny AK, Makuny D, Krishnan M P A, Poyil RC, Raveendran V. Validation of Dolphin dosimetry in three dimensional patient-specific quality assurance programme. Rep Pract Oncol Radiother 2019; 24:481-490. [PMID: 31452629 DOI: 10.1016/j.rpor.2019.07.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 05/15/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022] Open
Abstract
Aim The aim of this study is to commission and validate Dolphin-Compass dosimetry as a patient-specific Quality Assurance (QA) device. Background The advancement of radiation therapy in terms of highly conformal delivery techniques demands a novel method of patient-specific QA. Dolphin-Compass system is a dosimetry solution capable of doing different QA in radiation therapy. Materials and methods Dolphin, air-vented ionization detector array mounted on Versa-HD Linear Accelerator (LINAC) was used for measurements. The Compass is a dose computation algorithm which requires modelling of LINAC head similar to other Treatment Planning Systems (TPS). The dosimetry system was commissioned after measuring the required beam data. The validation was performed by comparison of treatment plans generated in Monaco TPS against the measurement data. Different types of simple, complex, static and dynamic radiation fields and highly conformal treatment plans of patients were used in this study. Results For all field sizes, point doses obtained from Dolphin-Compass dosimetry were in good agreement with the corresponding TPS calculated values in most of the regions, except the penumbra, outside field and at build-up depth. The results of gamma passing rates of measurements by using different Multi-leaf Collimator patterns and Intensity Modulated Radiation Therapy fluence were also found to be in good correlation with the corresponding TPS values. Conclusions The commissioning and validation of dosimetry was performed with the help of various fields, MLC patterns and complex treatment plans. The present study also evaluated the efficiency of the 3D dosimetry system for the QA of complex treatment plans.
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Affiliation(s)
- Niyas Puzhakkal
- Department of Medical Physics, MVR Cancer Centre & Research Institute, Kozhikode, Kerala, India.,Department of Physics, Farook College, Kozhikode, Kerala, India
| | | | - Dinesh Makuny
- Department of Medical Physics, MVR Cancer Centre & Research Institute, Kozhikode, Kerala, India
| | - Arun Krishnan M P
- Department of Medical Physics, MVR Cancer Centre & Research Institute, Kozhikode, Kerala, India
| | - Ranjith C Poyil
- Department of Medical Physics, MVR Cancer Centre & Research Institute, Kozhikode, Kerala, India
| | - Vysakh Raveendran
- Department of Medical Physics, MVR Cancer Centre & Research Institute, Kozhikode, Kerala, India
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Xie K, Sun H, Gao L, Sui J, Lin T, Ni X. A study on the correlation between radiation field size and gamma index passing rate for MatriXX. Medicine (Baltimore) 2019; 98:e16536. [PMID: 31348271 PMCID: PMC6709154 DOI: 10.1097/md.0000000000016536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 06/26/2019] [Accepted: 06/27/2019] [Indexed: 12/02/2022] Open
Abstract
This study aimed to analyze the influence of the radiation field size on the passing rate of the treatment planning system using MatriXX if the field irradiated the circuit.Two sets of static fields which were 10 cm and 30 cm in the left-right direction (X), and was 31 cm to 40 cm in gun-target direction (Y) were designed. In these fields, the gantry was 0 and the monitor units were 200 MU. Two plans from an esophagus carcinoma patient with a planning target volume of 86.4 cm and a cervical carcinoma patient with a planning target volume (PTV) of 2094.1 cm were chosen. The passing rates of these plans were gained without and with protecting the circuit area from lead alloys. The gamma analysis was used and the standard was set to 3%/3 mm.The verification passing rate decreased from 95.0% to 69.2% when X was 10 cm while Y increased from 31 cm to 40 cm. With the protection from low melting point lead alloys, the passing rate was from 96.2% to 89.6%. The results of the second set of plans without lead alloys were similar but the passing rate decreased more sharply. The passing rates of the 2 patients were 99.5% and 57.1%. With the protection of the lead alloys, their passing rates were 99.8% and 72.1%, respectively.The results showed that with the increase of the radiation field size in the Y direction, more areas were irradiated in the circuit, and the passing rate gradually decreases and dropped sharply at a certain threshold. After putting lead alloys above the circuit, the passing rate was much better in the static field but was still less than 90% in the second patient volumetric modulated arc therapy (VMAT) because the circuit was irradiate in other directions. In daily QA, we should pay attention to these patients with long size tumor.
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Affiliation(s)
- Kai Xie
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Hongfei Sun
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Liugang Gao
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Jianfeng Sui
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Tao Lin
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Xinye Ni
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
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Quality assurance of linear accelerator: a comprehensive system using electronic portal imaging device. JOURNAL OF RADIOTHERAPY IN PRACTICE 2019. [DOI: 10.1017/s146039691800050x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractAimThe Electronic Portal Imaging Device (EPID), primarily used for patient setup during radiotherapy sessions is also used for dosimetric measurements. In the present study, the feasibility of EPID in both machine and patient-specific quality assurance (QA) are investigated. We have developed a comprehensive software tool for effective utilisation of EPID in our institutional QA protocol.Materials and methodsPortal Vision aS1000, amorphous silicon portal detector attached to Clinac iX—Linear Accelerator (LINAC) was used to measure daily profile and output constancy, various Multi-Leaf Collimator (MLC) checks and patient plan verification. Different QA plans were generated with the help of Eclipse Treatment Planning System (TPS) and MLC shaper software. The indigenously developed MATLAB programs were used for image analysis. Flatness, symmetry, output constancy, Field Width at Half Maximum (FWHM) and fluence comparison were studied from images obtained from TPS and EPID dosimetry.ResultsThe 3 years institutional data of profile constancy and patient-specific QA measured using EPID were found within the acceptable limits. The daily output of photon beam correlated with the output obtained through solid phantom measurements. The Pearson correlation coefficients are 0.941 (p = 0.0001), 0.888 (p = 0.0188) and 0.917 (p = 0.0007) for the years of 2014, 2015 and 2016, respectively. The accuracy of MLC for shaping complex treatment fields was studied in terms of FWHM at different portions of various fields, showed good agreement between TPS-generated and EPID-measured MLC positions. The comparison of selected patient plans in EPID with an independent 2D array detector system showed statistically significant correlation between these two systems. Percentage difference between TPS computed and EPID measured fluence maps calculated for number of patients using MATLAB code also exhibited the validity of those plans for treatment.
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Howitz S, Wiezorek T, Wittig A, Vorwerk H, Zink K. Fluence-weighted average subfield size in helical TomoTherapy. Z Med Phys 2019; 29:337-348. [PMID: 31056376 DOI: 10.1016/j.zemedi.2019.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/29/2019] [Accepted: 03/30/2019] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Helical TomoTherapy allows a highly conformal dose distribution to complex target geometries with a good protection of organs at risk. However, the small field sizes associated with this method are a possible source of dosimetrical uncertainties. The IAEA has published detector-specific field output correction factors for static fields of the TomoTherapy in the TRS483. This work investigates the average subfield size of helical TomoTherapy plans. MATERIAL AND METHODS A new parameter for helical TomoTherapy was defined - the fluence-weighted average subfield size. The subfield sizes were extracted from the leaf-opening time sinograms in the RT-plan files for 30 clinical prostate and head and neck plans and were put in relation to Delat4 Phantom+ measurement results. Additionally the influence of planning parameters on the subfield size was studied by varying the modulation factor, number of iterations and pitch in the dose optimization and calculation for three different clinical indications H&N, prostate and rectum cancer. Selected plans were dosimetrically verified by Delta4 measurements to examine the reliability in dependence of the average subfield size. Furthermore, the impact of the planning parameters on a) the dose distribution, with regard to the planning target volume and regions at risks, and b) machine characteristics such as delivery time, actual modulation factor and leaf-opening times were evaluated. RESULTS The average equivalent square subfield lengths (s¯eq) of the two investigated indications did not differ significantly - prostate plans: 2.75±0.14cm and H&N plans: 2.70±0.16cm, both with a jaw width of 2.5cm. No correlation between field size and measured dose deviation was detected. The number of iterations and the modulation factor have a considerable influence on the average subfield size. The higher the planned modulation factor and the more iterations are used during optimization, the smaller is the subfield size. In our pilot study plans were calculated with field sizes s¯eq between 4.2cm and 1.7cm, with a jaw width of 2.5cm. Again, the measurement results of Delta4 showed no significant deviation from the doses calculated by the TomoTherapy planning system for the whole range of subfield sizes, and no significant correlation between field sizes and dose deviations was found. As expected, the clinical dose distribution improved with increasing modulation factor and an increasing number of iterations. The compromise between an improved dose distribution and smaller s¯eq was shown. CONCLUSION In this work, a method was presented to determine the average subfield size for helical TomoTherapy plans. The response of the Delta4 did not show any dependence on field size in the range of the field sizes covered by the studied plans. The influence of the subfield sizes on other dosimetry systems remains to be investigated.
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Affiliation(s)
- Simon Howitz
- University Hospital Jena, Department of Radiation Oncology, Germany; Institute for Medical Physics and Radiation Protection IMPS, University of Applied Science - THM, Giessen, Germany; Philipps-University, Marburg, Germany.
| | - Tilo Wiezorek
- University Hospital Jena, Department of Radiation Oncology, Germany
| | - Andrea Wittig
- University Hospital Jena, Department of Radiation Oncology, Germany
| | | | - Klemens Zink
- Institute for Medical Physics and Radiation Protection IMPS, University of Applied Science - THM, Giessen, Germany; University Medical Center Giessen-Marburg, Department of Radiation Oncology, Germany; Frankfurt Institute for Advanced Studies (FIAS), Frankfurt, Germany
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Wilson LJ, Newhauser WD, Schneider CW. An objective method to evaluate radiation dose distributions varying by three orders of magnitude. Med Phys 2019; 46:1888-1895. [PMID: 30714163 DOI: 10.1002/mp.13420] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/26/2018] [Accepted: 01/24/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Modern radiotherapy practices typically report the absorbed dose (D) within the 5% relative isodose volume (i.e., the therapeutic dose region) to an accuracy of 3%-5%. Gamma-index analysis, the most commonly used method to evaluate dosimetric accuracy, has low sensitivity to discrepancies that occur outside of this region. The objective of this study was to develop an evaluation method with high sensitivity across dose distributions spanning three orders of magnitude. METHODS We generalized the gamma index to include an additional criterion, the absolute absorbed dose difference, specifically for the low-dose region (i.e., D ≤ 5%). We also proposed a method to objectively select the appropriate magnitudes for relative-dose-difference, absolute-dose-difference, and distance-to-agreement criteria. We demonstrated the generalized gamma-index method by first finding the appropriate generalized gamma-index agreement criteria at an interval of specified passing rates. Next, we used the generalized gamma index to evaluate one-, two-, and three-dimensional absorbed dose distributions in a water-box phantom and voxelized patient geometry. RESULTS Generalized gamma-index passing rates for one-, two-, and three-dimensional dose distributions were 55.4%, 44.5%, and 8.9%, respectively. Traditional gamma-index passing rates were 100%, 97.8%, and 96.4%, respectively. These results reveal that the generalized method has adequate sensitivity in all regions (i.e., therapeutic and low dose). Additionally, the algorithmic determination of triplets of agreement criteria revealed that they are strong functions of the specified passing rate. CONCLUSIONS The major finding of this work is that the proposed method provides an objective evaluation of the agreement of dose distributions spanning three orders of magnitude. In particular, this generalized method correctly characterized dosimetric agreement in the low-dose region, which was not possible by traditional methods. The proposed algorithmic selection of agreement criteria decreased subjectivity and requirements of user judgment and skill. This method could find utility in a variety of applications including dose-algorithm development and translation.
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Affiliation(s)
- Lydia J Wilson
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803-4001, USA
| | - Wayne D Newhauser
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803-4001, USA.,Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, LA, 70809, USA
| | - Christopher W Schneider
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803-4001, USA
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Wu S, Chen J, Li Z, Qiu Q, Wang X, Li C, Yin Y. Analysis of dose verification results for 924 intensity-modulated radiation therapy plans. PRECISION RADIATION ONCOLOGY 2018. [DOI: 10.1002/pro6.58] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Shizhang Wu
- Department of Radiation Oncology; Shandong Cancer Hospital to Shandong University; Shandong Academy of Medical Sciences; Jinan China
| | - Jinhu Chen
- Department of Radiation Oncology; Shandong Cancer Hospital to Shandong University; Shandong Academy of Medical Sciences; Jinan China
| | - Zhenjiang Li
- Department of Radiation Oncology; Shandong Cancer Hospital to Shandong University; Shandong Academy of Medical Sciences; Jinan China
| | - Qingtao Qiu
- Department of Radiation Oncology; Shandong Cancer Hospital to Shandong University; Shandong Academy of Medical Sciences; Jinan China
| | - Xingli Wang
- Department of Radiation Oncology; Shandong Cancer Hospital to Shandong University; Shandong Academy of Medical Sciences; Jinan China
| | - Chengqiang Li
- Department of Radiation Oncology; Shandong Cancer Hospital to Shandong University; Shandong Academy of Medical Sciences; Jinan China
| | - Yong Yin
- Department of Radiation Oncology; Shandong Cancer Hospital to Shandong University; Shandong Academy of Medical Sciences; Jinan China
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Pogson E, Arumugam S, Hansen C, Currie M, Blake S, Roberts N, Carolan M, Vial P, Alharthi T, Holloway L, Thwaites D. Comparison of multi-institutional pre-treatment verification for VMAT of nasopharynx with delivery errors. Phys Med 2018; 53:25-31. [DOI: 10.1016/j.ejmp.2018.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/19/2018] [Accepted: 07/21/2018] [Indexed: 10/28/2022] Open
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Urso P, Lorusso R, Marzoli L, Corletto D, Imperiale P, Pepe A, Bianchi L. Practical application of Octavius ® -4D: Characteristics and criticalities for IMRT and VMAT verification. J Appl Clin Med Phys 2018; 19:517-524. [PMID: 30009564 PMCID: PMC6123102 DOI: 10.1002/acm2.12412] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/28/2018] [Accepted: 06/07/2018] [Indexed: 11/12/2022] Open
Abstract
Octavius®‐4D is a very effective device in radiotherapy treatment quality assurance (QA), due to its simple set‐up and analysis package. However, even if it is widely used, its main characteristics and criticalities were only partially investigated. Taking start from its commissioning, the aim of this work was to study the main dependencies of the device response. The outcome dependence was studied comparing results by different delivery techniques [Intensity Modulated Radiation Therapy, IMRT (n = 29) and RapidArc, RA (n = 15)], anatomical regions [15 head/neck, 19 pelvis and 10 pancreas] and linear accelerators [DHX (n = 14) and Trilogy (n = 30)]. Moreover, the agreement dependency on the section of the phantom was assessed. Plan evaluations obtained by 2D, 3D, and volumetric γ‐index (both local and global) were also compared. Generally, high dose gradient resulted critically managed by the assembly, with a smoother effect in RA technique. Worse agreements emerged in the 2D γ‐index vs those of 3D and volumetric (P < 0.001), that were instead statistically comparable in global metric (P > 0.300). Volumetric plan evaluation was coherent with the average of passing rates on the 3 phantom axes (r ≥ 0.9), but transversal section provided best agreements vs sagittal and coronal ones (P < 0.050). The three studied districts furnished comparable results (P > 0.050) while the two LINACs provided different agreements (P < 0.005). The study pointed out that the phantom transversal section better fits the planned dose distribution, so this should be accounted when a two‐dimensional evaluation is needed. Moreover, the major reliability of the 3D metric with respect to the 2D one, as it better agrees with the dosimetric evaluation on the whole volume, suggests that it should be preferred in a two‐dimensional evaluation. Better agreements, obtained with RA vs IMRT technique, confirm that Octavius®‐4D is specifically conceived for rotational delivery. Lastly, the assembly resulted sensitive to different technology.
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Affiliation(s)
- Patrizia Urso
- Department of Medical Physics, A.S.S.T. Valle Olona, Busto Arsizio, Italy
| | - Rita Lorusso
- Department of Medical Physics, A.S.S.T. Valle Olona, Busto Arsizio, Italy
| | - Luca Marzoli
- Department of Medical Physics, A.S.S.T. Valle Olona, Busto Arsizio, Italy
| | - Daniela Corletto
- Department of Medical Physics, A.S.S.T. Valle Olona, Busto Arsizio, Italy
| | - Paolo Imperiale
- Department of Medical Physics, A.S.S.T. Valle Olona, Busto Arsizio, Italy
| | - Annalisa Pepe
- Department of Medical Physics, A.S.S.T. Valle Olona, Busto Arsizio, Italy
| | - Lorenzo Bianchi
- Department of Medical Physics, A.S.S.T. Valle Olona, Busto Arsizio, Italy
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Wootton LS, Nyflot MJ, Chaovalitwongse WA, Ford E. Error Detection in Intensity-Modulated Radiation Therapy Quality Assurance Using Radiomic Analysis of Gamma Distributions. Int J Radiat Oncol Biol Phys 2018; 102:219-228. [PMID: 30102197 DOI: 10.1016/j.ijrobp.2018.05.033] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 04/10/2018] [Accepted: 05/13/2018] [Indexed: 10/16/2022]
Abstract
PURPOSE To improve the detection of errors in intensity-modulated radiation therapy (IMRT) with a novel method that uses quantitative image features from radiomics to analyze gamma distributions generated during patient specific quality assurance (QA). METHODS AND MATERIALS One hundred eighty-six IMRT beams from 23 patient treatments were delivered to a phantom and measured with electronic portal imaging device dosimetry. The treatments spanned a range of anatomic sites; half were head and neck treatments, and the other half were drawn from treatments for lung and rectal cancers, sarcoma, and glioblastoma. Planar gamma distributions, or gamma images, were calculated for each beam using the measured dose and calculated doses from the 3-dimensional treatment planning system under various scenarios: a plan without errors and plans with either simulated random or systematic multileaf collimator mispositioning errors. The gamma images were randomly divided into 2 sets: a training set for model development and testing set for validation. Radiomic features were calculated for each gamma image. Error detection models were developed by training logistic regression models on these radiomic features. The models were applied to the testing set to quantify their predictive utility, determined by calculating the area under the curve (AUC) of the receiver operator characteristic curve, and were compared with traditional threshold-based gamma analysis. RESULTS The AUC of the random multileaf collimator mispositioning model on the testing set was 0.761 compared with 0.512 for threshold-based gamma analysis. The AUC for the systematic mispositioning model was 0.717 versus 0.660 for threshold-based gamma analysis. Furthermore, the models could discriminate between the 2 types of errors simulated here, exhibiting AUCs of approximately 0.5 (equivalent to random guessing) when applied to the error they were not designed to detect. CONCLUSIONS The feasibility of error detection in patient-specific IMRT QA using radiomic analysis of QA images has been demonstrated. This methodology represents a substantial step forward for IMRT QA with improved sensitivity and specificity over current QA methods and the potential to distinguish between different types of errors.
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Affiliation(s)
- Landon S Wootton
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington.
| | - Matthew J Nyflot
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington; Department of Radiology, University of Washington School of Medicine, Seattle, Washington
| | - W Art Chaovalitwongse
- Department of Radiology, University of Washington School of Medicine, Seattle, Washington; Department of Industrial Engineering, University of Arkansas, Fayetteville, Arkansas
| | - Eric Ford
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, Washington
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García-Garduño OA, Rodríguez-Ávila MA, Lárraga-Gutiérrez JM. Detector-specific correction factors in radiosurgery beams and their impact on dose distribution calculations. PLoS One 2018; 13:e0196393. [PMID: 29763446 PMCID: PMC5953445 DOI: 10.1371/journal.pone.0196393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 04/12/2018] [Indexed: 12/01/2022] Open
Abstract
Silicon-diode-based detectors are commonly used for the dosimetry of small radiotherapy beams due to their relatively small volumes and high sensitivity to ionizing radiation. Nevertheless, silicon-diode-based detectors tend to over-respond in small fields because of their high density relative to water. For that reason, detector-specific beam correction factors ( kQclin,Qmsrfclin,fmsr) have been recommended not only to correct the total scatter factors but also to correct the tissue maximum and off-axis ratios. However, the application of kQclin,Qmsrfclin,fmsr to in-depth and off-axis locations has not been studied. The goal of this work is to address the impact of the correction factors on the calculated dose distribution in static non-conventional photon beams (specifically, in stereotactic radiosurgery with circular collimators). To achieve this goal, the total scatter factors, tissue maximum, and off-axis ratios were measured with a stereotactic field diode for 4.0-, 10.0-, and 20.0-mm circular collimators. The irradiation was performed with a Novalis® linear accelerator using a 6-MV photon beam. The detector-specific correction factors were calculated and applied to the experimental dosimetry data for in-depth and off-axis locations. The corrected and uncorrected dosimetry data were used to commission a treatment planning system for radiosurgery planning. Various plans were calculated with simulated lesions using the uncorrected and corrected dosimetry. The resulting dose calculations were compared using the gamma index test with several criteria. The results of this work presented important conclusions for the use of detector-specific beam correction factors ( kQclin,Qmsrfclin,fmsr) in a treatment planning system. The use of kQclin,Qmsrfclin,fmsr for total scatter factors has an important impact on monitor unit calculation. On the contrary, the use of kQclin,Qmsrfclin,fmsr for tissue-maximum and off-axis ratios has not an important impact on the dose distribution calculation by the treatment planning system. This conclusion is only valid for the combination of treatment planning system, detector, and correction factors used in this work; however, this technique can be applied to other treatment planning systems, detectors, and correction factors.
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Affiliation(s)
- Olivia A. García-Garduño
- Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía, México City, México
- * E-mail:
| | - Manuel A. Rodríguez-Ávila
- Posgrado en Ciencias Físicas, Instituto de Física, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, México
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Miften M, Olch A, Mihailidis D, Moran J, Pawlicki T, Molineu A, Li H, Wijesooriya K, Shi J, Xia P, Papanikolaou N, Low DA. Tolerance limits and methodologies for IMRT measurement-based verification QA: Recommendations of AAPM Task Group No. 218. Med Phys 2018; 45:e53-e83. [DOI: 10.1002/mp.12810] [Citation(s) in RCA: 373] [Impact Index Per Article: 62.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 12/10/2017] [Accepted: 01/11/2018] [Indexed: 11/07/2022] Open
Affiliation(s)
- Moyed Miften
- Department of Radiation Oncology; University of Colorado School of Medicine; Aurora CO USA
| | - Arthur Olch
- Department of Radiation Oncology; University of Southern California and Radiation Oncology Program; Childrens Hospital of Los Angeles; Los Angeles CA USA
| | - Dimitris Mihailidis
- Department of Radiation Oncology; University of Pennsylvania; Perelman Center for Advanced Medicine; Philadelphia PA USA
| | - Jean Moran
- Department of Radiation Oncology; University of Michigan; Ann Arbor MI USA
| | - Todd Pawlicki
- Department of Radiation Oncology; University of California San Diego; La Jolla CA USA
| | - Andrea Molineu
- Radiological Physics Center; UT MD Anderson Cancer Center; Houston TX USA
| | - Harold Li
- Department of Radiation Oncology; Washington University; St. Louis MO USA
| | - Krishni Wijesooriya
- Department of Radiation Oncology; University of Virginia; Charlottesville VA USA
| | - Jie Shi
- Sun Nuclear Corporation; Melbourne FL USA
| | - Ping Xia
- Department of Radiation Oncology; The Cleveland Clinic; Cleveland OH USA
| | - Nikos Papanikolaou
- Department of Medical Physics; University of Texas Health Sciences Center; San Antonio TX USA
| | - Daniel A. Low
- Department of Radiation Oncology; University of California Los Angeles; Los Angeles CA USA
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Shen L, Chen S, Zhu X, Han C, Zheng X, Deng Z, Zhou Y, Gong C, Xie C, Jin X. Multidimensional correlation among plan complexity, quality and deliverability parameters for volumetric-modulated arc therapy using canonical correlation analysis. JOURNAL OF RADIATION RESEARCH 2018; 59:207-215. [PMID: 29415196 PMCID: PMC5950931 DOI: 10.1093/jrr/rrx100] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 02/16/2017] [Indexed: 06/08/2023]
Abstract
A multidimensional exploratory statistical method, canonical correlation analysis (CCA), was applied to evaluate the impact of complexity parameters on the plan quality and deliverability of volumetric-modulated arc therapy (VMAT) and to determine parameters in the generation of an ideal VMAT plan. Canonical correlations among complexity, quality and deliverability parameters of VMAT, as well as the contribution weights of different parameters were investigated with 71 two-arc VMAT nasopharyngeal cancer (NPC) patients, and further verified with 28 one-arc VMAT prostate cancer patients. The average MU and MU per control point (MU/CP) for two-arc VMAT plans were 702.6 ± 55.7 and 3.9 ± 0.3 versus 504.6 ± 99.2 and 5.6 ± 1.1 for one-arc VMAT plans, respectively. The individual volume-based 3D gamma passing rates of clinical target volume (γCTV) and planning target volume (γPTV) for NPC and prostate cancer patients were 85.7% ± 9.0% vs 92.6% ± 7.8%, and 88.0% ± 7.6% vs 91.2% ± 7.7%, respectively. Plan complexity parameters of NPC patients were correlated with plan quality (P = 0.047) and individual volume-based 3D gamma indices γ(IV) (P = 0.01), in which, MU/CP and segment area (SA) per control point (SA/CP) were weighted highly in correlation with γ(IV) , and SA/CP, percentage of CPs with SA < 5 × 5 cm2 (%SA < 5 × 5 cm2) and PTV volume were weighted highly in correlation with plan quality with coefficients of 0.98, 0.68 and -0.99, respectively. Further verification with one-arc VMAT plans demonstrated similar results. In conclusion, MU, SA-related parameters and PTV volume were found to have strong effects on the plan quality and deliverability.
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Affiliation(s)
- Lanxiao Shen
- Department of Radiotherapy and Chemotherapy, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Shan Chen
- Elekta Instrument (Shanghai) Ltd, No. 1528 Century Avenue, Shanghai, China
| | - Xiaoyang Zhu
- Department of Radiation Oncology, The 2nd Affiliated Hospital of Medical College of Zhejiang University, Hangzhou, China
| | - Ce Han
- Department of Radiotherapy and Chemotherapy, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiaomin Zheng
- Department of Radiotherapy and Chemotherapy, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Zhenxiang Deng
- Department of Radiotherapy and Chemotherapy, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yongqiang Zhou
- Department of Radiotherapy and Chemotherapy, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Changfei Gong
- Department of Radiotherapy and Chemotherapy, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Congying Xie
- Department of Radiotherapy and Chemotherapy, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiance Jin
- Department of Radiotherapy and Chemotherapy, The 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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Qiu J, Lv B, Fu M, Wang X, Zheng X, Zhuo W. 18 F-Fluoromisonidazole positron emission tomography/CT-guided volumetric-modulated arc therapy-based dose escalation for hypoxic subvolume in nasopharyngeal carcinomas: A feasibility study. Head Neck 2017; 39:2519-2527. [PMID: 28963789 DOI: 10.1002/hed.24925] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 04/26/2017] [Accepted: 07/17/2017] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The purpose of this study is to investigate the feasibility of a simultaneously integrated boost to the hypoxic subvolume of nasopharyngeal carcinomas (NCPs) under the guidance of 18 F-fluoromisonidazole (FMISO) positron emission tomography (PET)/CT using volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) techniques. METHODS Eight patients with NPC were treated with simultaneous integrated boost-IMRT (treatment plan named IMRT70) with dose prescriptions of 70 Gy, 66 Gy, 60 Gy, and 54 Gy to the gross tumor volume (GTV), positive neck nodes, the planning target volume (PTV), and the clinically negative neck, respectively. Based on the same datasets, experimental plans with the same dose prescription plus a dose boost of 14 Gy (an escalation of 20% of the prescription dose) to the hypoxic volume target contoured on the pretreatment 18 F-FMISO PET/CT imaging were generated using IMRT and VMAT techniques, respectively (represented by IMRT84 and VMAT84). Two or more arcs (approximately 2-2.5 arcs, totally rotating angle <1000 degrees) were used in VMAT plans and 9 equally separated fields in IMRT plans. Dosimetric parameters, total monitor units, and delivery time were calculated for comparative study of plan quality and delivery efficiency between IMRT84 and VMAT84. RESULTS In experimental plans, hypoxic target volumes successfully received the prescribed dose of 84 Gy in compliance with other dose constraints with either the IMRT technique or the VMAT technique. In terms of the target coverage, dose homogeneity, and organs at risk (OAR) sparing, there was no statistically significant difference between the actual treatment plan of IMRT70 and experimental plans. The total monitor unit of VMAT84 (525.7 ± 39.8) was significantly less than IMRT70 (1171.5 ± 167; P = .001) and IMRT84 (1388.3 ± 151.0; P = .001) per fraction, with 55.1% and 62.1% reduction. The average machine delivery time was 3.5 minutes for VMAT plans in comparison with approximately 8 minutes for IMRT plans, resulting in a reduction factor of 56.2%. For experimental plans, the 3D gamma index average was over 98.0% with no statistical significant difference when a 3%/3 mm gamma passing rate criteria was used. CONCLUSION With the guidance of 18 F-FMISO PET/CT imaging, dose escalation to hypoxic zones within NPC could be achieved and delivered efficiently with the VMAT technique in comparison with the IMRT technique.
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Affiliation(s)
- Jianjian Qiu
- Institute of Radiation Medicine, Fudan University, Shanghai, China
| | - Bo Lv
- Department of Radiation Oncology, Fudan University Huadong Hospital, Shanghai, China
| | - Meina Fu
- Department of Radiation Oncology, Fudan University Huadong Hospital, Shanghai, China
| | - Xianglian Wang
- Department of Radiation Oncology, Fudan University Huadong Hospital, Shanghai, China
| | - Xiangpeng Zheng
- Department of Radiation Oncology, Fudan University Huadong Hospital, Shanghai, China
| | - Weihai Zhuo
- Institute of Radiation Medicine, Fudan University, Shanghai, China
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Hamatani N, Sumida I, Takahashi Y, Oda M, Seo Y, Isohashi F, Tamari K, Ogawa K. Three-dimensional dose prediction and validation with the radiobiological gamma index based on a relative seriality model for head-and-neck IMRT. JOURNAL OF RADIATION RESEARCH 2017; 58:701-709. [PMID: 28430990 PMCID: PMC5737806 DOI: 10.1093/jrr/rrx017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/30/2016] [Indexed: 06/07/2023]
Abstract
This study proposes a quality assurance (QA) method incorporating radiobiological factors based on the QUANTEC-determined tumor control probability and the normal tissue complication probability (NTCP) of head-and-neck intensity-modulated radiation therapy (HN-IMRT). Per-beam measurements were conducted for 20 cases using a 2D detector array. Three-dimensional predicted dose distributions within targets and organs at risk were reconstructed based on the per-beam QA results derived from differences between planned and measured doses. Under the predicted dose distributions, the differences between the physical and radiobiological gamma indices (PGI and RGI, respectively) based on the relative seriality (RS) model were evaluated. The NTCP values in the RS and Niemierko models were compared. The dose covers 98% (D98%) of the clinical target volume (CTV) decreased by 3.2% (P < 0.001), and the mean dose of the ipsilateral parotid increased by 6.3% (P < 0.001) compared with the original dose. RGI passing rates in the CTV and brain stem were greater than PGI ones by 5.8% (P < 0.001) and 2.0% (P < 0.001), respectively. The RS model's average NTCP values for the ipsilateral and contralateral parotids under the original dose were smaller than those of the Niemierko model by 9.0% (P < 0.001) and 7.0% (P < 0.001), respectively. The 3D predicted dose evaluation with RGI based on the RS model was introduced for QA of HN-IMRT, leading to dose evaluation for each organ with consideration of the radiobiological effect. This method constitutes a rational way to perform QA of HN-IMRT in clinical practice.
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Affiliation(s)
- Noriaki Hamatani
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Iori Sumida
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Yutaka Takahashi
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Michio Oda
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
- Department of Radiology, Osaka University Hospital, 2-15 Yamada-oka, Suita, Osaka 565-0871,Japan
| | - Yuji Seo
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Fumiaki Isohashi
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Keisuke Tamari
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Kazuhiko Ogawa
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
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Ohira S, Ueda Y, Isono M, Masaoka A, Hashimoto M, Miyazaki M, Takashina M, Koizumi M, Teshima T. Can clinically relevant dose errors in patient anatomy be detected by gamma passing rate or modulation complexity score in volumetric-modulated arc therapy for intracranial tumors? JOURNAL OF RADIATION RESEARCH 2017; 58:685-692. [PMID: 28339918 PMCID: PMC5737460 DOI: 10.1093/jrr/rrx006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/28/2016] [Indexed: 06/06/2023]
Abstract
We investigated whether methods conventionally used to evaluate patient-specific QA in volumetric-modulated arc therapy (VMAT) for intracranial tumors detect clinically relevant dosimetric errors. VMAT plans with coplanar arcs were designed for 37 intracranial tumors. Dosimetric accuracy was validated by using a 3D array detector. Dose deviations between the measured and planned doses were evaluated by gamma analysis. In addition, modulation complexity score for VMAT (MCSv) for each plan was calculated. Three-dimensional dose distributions in patient anatomy were reconstructed using 3DVH software, and clinical deviations in dosimetric parameters between the 3DVH doses and planned doses were calculated. The gamma passing rate (GPR)/MCSv and the clinical dose deviation were evaluated using Pearson's correlation coefficient. Significant correlation (P < 0.05) between the clinical dose deviation and GPR was observed with both the 3%/3 mm and 2%/2 mm criteria in clinical target volume (D99), brain (D2), brainstem (D2) and chiasm (D2), albeit that the correlations were not 'strong' (0.38 < |r| < 0.54). The maximum dose deviations of brainstem were up to 4.9 Gy and 2.9 Gy for Dmax and D%, respectively in the case of high GPR (98.2% with 3%/3 mm criteria). Regarding MCSv, none of the evaluated organs showed a significant correlation with clinical dose deviation, and correlations were 'weak' or absent (0.01 < |r| < 0.21). The use of high GPR and MCSv values does not always detect dosimetric errors in a patient. Therefore, in-depth analysis with the DVH for patient-specific QA is considered to be preferable for guaranteeing safe dose delivery.
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Affiliation(s)
- Shingo Ohira
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yoshihiro Ueda
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masaru Isono
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
| | - Akira Masaoka
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
| | - Misaki Hashimoto
- Department of Radiation Oncology, Yao Municipal Hospital, Yao, Japan
| | - Masayoshi Miyazaki
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
| | - Masaaki Takashina
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masahiko Koizumi
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Teruki Teshima
- Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Nakamichi 1-3-3, Higashinari-ku, Osaka, 537-8511, Japan
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Srivastava SP, Cheng CW, Das IJ. The dosimetric and radiobiological impact of calculation grid size on head and neck IMRT. Pract Radiat Oncol 2017; 7:209-217. [DOI: 10.1016/j.prro.2016.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 09/02/2016] [Accepted: 10/05/2016] [Indexed: 10/20/2022]
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Steers JM, Fraass BA. IMRT QA: Selecting gamma criteria based on error detection sensitivity. Med Phys 2016; 43:1982. [PMID: 27036593 DOI: 10.1118/1.4943953] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The gamma comparison is widely used to evaluate the agreement between measurements and treatment planning system calculations in patient-specific intensity modulated radiation therapy (IMRT) quality assurance (QA). However, recent publications have raised concerns about the lack of sensitivity when employing commonly used gamma criteria. Understanding the actual sensitivity of a wide range of different gamma criteria may allow the definition of more meaningful gamma criteria and tolerance limits in IMRT QA. We present a method that allows the quantitative determination of gamma criteria sensitivity to induced errors which can be applied to any unique combination of device, delivery technique, and software utilized in a specific clinic. METHODS A total of 21 DMLC IMRT QA measurements (ArcCHECK®, Sun Nuclear) were compared to QA plan calculations with induced errors. Three scenarios were studied: MU errors, multi-leaf collimator (MLC) errors, and the sensitivity of the gamma comparison to changes in penumbra width. Gamma comparisons were performed between measurements and error-induced calculations using a wide range of gamma criteria, resulting in a total of over 20 000 gamma comparisons. Gamma passing rates for each error class and case were graphed against error magnitude to create error curves in order to represent the range of missed errors in routine IMRT QA using 36 different gamma criteria. RESULTS This study demonstrates that systematic errors and case-specific errors can be detected by the error curve analysis. Depending on the location of the error curve peak (e.g., not centered about zero), 3%/3 mm threshold = 10% at 90% pixels passing may miss errors as large as 15% MU errors and ±1 cm random MLC errors for some cases. As the dose threshold parameter was increased for a given %Diff/distance-to-agreement (DTA) setting, error sensitivity was increased by up to a factor of two for select cases. This increased sensitivity with increasing dose threshold was consistent across all studied combinations of %Diff/DTA. Criteria such as 2%/3 mm and 3%/2 mm with a 50% threshold at 90% pixels passing are shown to be more appropriately sensitive without being overly strict. However, a broadening of the penumbra by as much as 5 mm in the beam configuration was difficult to detect with commonly used criteria, as well as with the previously mentioned criteria utilizing a threshold of 50%. CONCLUSIONS We have introduced the error curve method, an analysis technique which allows the quantitative determination of gamma criteria sensitivity to induced errors. The application of the error curve method using DMLC IMRT plans measured on the ArcCHECK® device demonstrated that large errors can potentially be missed in IMRT QA with commonly used gamma criteria (e.g., 3%/3 mm, threshold = 10%, 90% pixels passing). Additionally, increasing the dose threshold value can offer dramatic increases in error sensitivity. This approach may allow the selection of more meaningful gamma criteria for IMRT QA and is straightforward to apply to other combinations of devices and treatment techniques.
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Affiliation(s)
- Jennifer M Steers
- Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California 90048 and Physics and Biology in Medicine IDP, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| | - Benedick A Fraass
- Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California 90048
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Deng X, Han C, Chen S, Xie C, Yi J, Zhou Y, Zheng X, Deng Z, Jin X. Dosimetric benefits of intensity-modulated radiotherapy and volumetric-modulated arc therapy in the treatment of postoperative cervical cancer patients. J Appl Clin Med Phys 2016; 18:25-31. [PMID: 28291936 PMCID: PMC5689869 DOI: 10.1002/acm2.12003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/06/2016] [Indexed: 12/02/2022] Open
Abstract
As the advantage of using complex volumetric‐modulated arc therapy (VMAT) in the treatment of gynecologic cancer has not yet been fully determined, the purpose of this study was to investigate the dosimetric advantages of VMAT by comparing directly with whole pelvic conformal radiotherapy (CRT) and intensity‐modulated radiotherapy (IMRT) in the treatment of 15 postoperative cervical cancer patients. Four‐field CRT, seven‐field IMRT, and two‐arc VMAT plans were generated for each patient with identical objective functions to achieve clinically acceptable dose distribution. Target coverage and OAR sparing differences were investigated through dose‐volume histogram (DVH) analysis. Nondosimtric differences between IMRT and VMAT were also compared. Target coverage presented by V95% were 88.9% ± 3.8%, 99.9% ± 0.07%, and 99.9% ± 0.1% for CRT, IMRT, and VMAT, respectively. Significant differences on conformal index (CI) and conformal number (CN) were observed with CIs of 0.37 ± 0.07, 0.55 ± 0.04, 0.61 ± 0.04, and CNs of 0.33 ± 0.06, 0.55 ± 0.04, 0.60 ± 0.04 for CRT, IMRT, and VMAT, respectively. IMRT and VMAT decreased the dose to bladder and rectum significantly compared with CRT. No significant differences on the Dmean, V45, and V30 of small bowel were observed among CRT, IMRT, and VMAT. However, VMAT (10.4 ± 4.8 vs. 19.8 ± 11.0, P = 0.004) and IMRT (12.3 ± 5.0 vs. 19.8 ± 11.0, P = 0.02) decreased V40, increased the Dmax of small bowel and the irradiation dose to femoral heads compared with CRT. VMAT irradiated less dose to bladder, rectum, small bowel and larger volume of health tissue with a lower dose (V5 and V10) compared with IMRT, although the differences were not statistical significant. In conclusion, VMAT and IMRT showed significant dosimetric advantages both on target coverage and OAR sparing compared with CRT in the treatment of postoperative cervical cancer. However, no significant difference between IMRT and VMAT was observed except for slightly better dose conformity, slightly less MU, and significant shorter delivery time achieved for VMAT.
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Affiliation(s)
- Xia Deng
- Radiotherapy and Chemotherapy Department, the 1st Affiliated Hospital of Wenhzou Medical University, Wenzhou, China
| | - Ce Han
- Radiotherapy and Chemotherapy Department, the 1st Affiliated Hospital of Wenhzou Medical University, Wenzhou, China
| | - Shan Chen
- Department of Clinical Solutions Support, Elekta Instrument (Shanghai) Ltd., Shanghai, China
| | - Congying Xie
- Radiotherapy and Chemotherapy Department, the 1st Affiliated Hospital of Wenhzou Medical University, Wenzhou, China
| | - Jinling Yi
- Radiotherapy and Chemotherapy Department, the 1st Affiliated Hospital of Wenhzou Medical University, Wenzhou, China
| | - Yongqiang Zhou
- Radiotherapy and Chemotherapy Department, the 1st Affiliated Hospital of Wenhzou Medical University, Wenzhou, China
| | - Xiaomin Zheng
- Radiotherapy and Chemotherapy Department, the 1st Affiliated Hospital of Wenhzou Medical University, Wenzhou, China
| | - Zhenxiang Deng
- Radiotherapy and Chemotherapy Department, the 1st Affiliated Hospital of Wenhzou Medical University, Wenzhou, China
| | - Xiance Jin
- Radiotherapy and Chemotherapy Department, the 1st Affiliated Hospital of Wenhzou Medical University, Wenzhou, China
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Ahmed S, Nelms B, Kozelka J, Zhang G, Moros E, Feygelman V. Validation of an improved helical diode array and dose reconstruction software using TG-244 datasets and stringent dose comparison criteria. J Appl Clin Med Phys 2016; 17:163-178. [PMID: 27929491 PMCID: PMC5690493 DOI: 10.1120/jacmp.v17i6.6414] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 08/09/2016] [Accepted: 08/08/2016] [Indexed: 11/23/2022] Open
Abstract
The original helical ArcCHECK (AC) diode array and associated software for 3D measurement‐guided dose reconstruction were characterized and validated; however, recent design changes to the AC required that the subject be revisited. The most important AC change starting in 2014 was a significant reduction in the overresponse of diodes to scattered radiation outside of the direct beam, accomplished by reducing the amount of high‐Z materials adjacent to the diodes. This change improved the diode measurement accuracy, but in the process invalidated the dose reconstruction models that were assembled based on measured data acquired with the older version of the AC. A correction mechanism was introduced in the reconstruction software (3DVH) to accommodate this and potential future design changes without requiring updating model parameters. For each permutation of AC serial number and beam model, the user can define in 3DVH a single correction factor which will be used to compensate for the difference in the out‐of‐field response between the new and original AC designs. The exact value can be determined by minimizing the dose‐difference with an ionization chamber or another independent dosimeter. A single value of 1.17, corresponding to the maximum measured out‐of‐field response difference between the new and old AC, provided satisfactory results for all studied energies (6X, 15X, and flattening filter‐free 10XFFF). A library of standard cases recommended by the AAPM TG‐244 Report was used for reconstructed dose verification. The overall difference between reconstructed dose and an ion chamber in a water‐equivalent phantom in the targets was 0.0% ± 1.4% (1 SD). The reconstructed dose on a homogeneous phantom was also compared to a biplanar diode dosimeter (Delta4) using gamma analysis with 2% (local dose‐error normalization)/2 mm/10% cutoff criteria. The mean agreement rate was 96.7% ± 3.7%. For the plans common with the previous comparison, the mean agreement rate was 98.3% ± 0.8%, essentially unchanged. We conclude that the proposed software modification adequately addresses the change in the dosimeter response. PACS number(s): 87.55Qr
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Patient-related quality assurance with different combinations of treatment planning systems, techniques, and machines : A multi-institutional survey. Strahlenther Onkol 2016; 193:46-54. [PMID: 27812732 DOI: 10.1007/s00066-016-1064-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 10/06/2016] [Indexed: 10/20/2022]
Abstract
PURPOSE This project compares the different patient-related quality assurance systems for intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) techniques currently used in the central Germany area with an independent measuring system. MATERIALS AND METHODS The participating institutions generated 21 treatment plans with different combinations of treatment planning systems (TPS) and linear accelerators (LINAC) for the QUASIMODO (Quality ASsurance of Intensity MODulated radiation Oncology) patient model. The plans were exposed to the ArcCHECK measuring system (Sun Nuclear Corporation, Melbourne, FL, USA). The dose distributions were analyzed using the corresponding software and a point dose measured at the isocenter with an ionization chamber. RESULTS According to the generally used criteria of a 10 % threshold, 3 % difference, and 3 mm distance, the majority of plans investigated showed a gamma index exceeding 95 %. Only one plan did not fulfill the criteria and three of the plans did not comply with the commonly accepted tolerance level of ±3 % in point dose measurement. CONCLUSION Using only one of the two examined methods for patient-related quality assurance is not sufficiently significant in all cases.
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Chung JB, Kang SW, Eom KY, Song C, Choi KS, Suh TS. Comparison of Dosimetric Performance among Commercial Quality Assurance Systems for Verifying Pretreatment Plans of Stereotactic Body Radiotherapy Using Flattening-Filter-Free Beams. J Korean Med Sci 2016; 31:1742-1748. [PMID: 27709851 PMCID: PMC5056205 DOI: 10.3346/jkms.2016.31.11.1742] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/19/2016] [Indexed: 11/20/2022] Open
Abstract
The purpose of this study was to compare the performance of different commercial quality assurance (QA) systems for the pretreatment verification plan of stereotactic body radiotherapy (SBRT) with volumetric arc therapy (VMAT) technique using a flattening-filter-free beam. The verification for 20 pretreatment cancer patients (seven lung, six spine, and seven prostate cancers) were tested using three QA systems (EBT3 film, I'mRT MatriXX array, and MapCHECK). All the SBRT-VMAT plans were optimized in the Eclipse (version 11.0.34) treatment planning system (TPS) using the Acuros XB dose calculation algorithm and were delivered to the Varian TrueBeam® accelerator equipped with a high-definition multileaf collimator. Gamma agreement evaluation was analyzed with the criteria of 2% dose difference and 2 mm distance to agreement (2%/2 mm) or 3%/3 mm. The highest passing rate (99.1% for 3%/3 mm) was observed on the MapCHECK system while the lowest passing rate was obtained on the film. The pretreatment verification results depend on the QA systems, treatment sites, and delivery beam energies. However, the delivery QA results for all QA systems based on the TPS calculation showed a good agreement of more than 90% for both the criteria. It is concluded that the three 2D QA systems have sufficient potential for pretreatment verification of the SBRT-VMAT plan.
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Affiliation(s)
- Jin Beom Chung
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Sang Won Kang
- Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Keun Yong Eom
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Changhoon Song
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Kyoung Sik Choi
- Department of Radiation Oncology, SAM Anyang Hospital, Anyang, Korea
| | - Tae Suk Suh
- Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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Camps S, van der Meer S, Verhaegen F, Fontanarosa D. Various approaches for pseudo-CT scan creation based on ultrasound to ultrasound deformable image registration between different treatment time points for radiotherapy treatment plan adaptation in prostate cancer patients. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/3/035018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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49
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Effect of fluence smoothing on the quality of intensity-modulated radiation treatment plans. Radiol Phys Technol 2016; 9:202-13. [DOI: 10.1007/s12194-016-0349-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 12/25/2022]
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50
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Kurosu K, Sumida I, Mizuno H, Otani Y, Oda M, Isohashi F, Seo Y, Suzuki O, Ogawa K. Curtailing patient-specific IMRT QA procedures from 2D dose error distribution. JOURNAL OF RADIATION RESEARCH 2016; 57:258-264. [PMID: 26661854 PMCID: PMC4915532 DOI: 10.1093/jrr/rrv084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 09/30/2015] [Accepted: 10/22/2015] [Indexed: 06/05/2023]
Abstract
A patient-specific quality assurance (QA) test is conducted to verify the accuracy of dose delivery. It generally consists of three verification processes: the absolute point dose difference, the planar dose differences at each gantry angle, and the planar dose differences by 3D composite irradiation. However, this imposes a substantial workload on medical physicists. The objective of this study was to determine whether our novel method that predicts the 3D delivered dose allows certain patient-specific IMRT QAs to be curtailed. The object was IMRT QA for the pelvic region with regard to point dose and composite planar dose differences. We compared measured doses, doses calculated in the treatment planning system, and doses predicted by in-house software. The 3D predicted dose was reconstructed from the per-field measurement by incorporating the relative dose error distribution into the original dose grid of each beam. All point dose differences between the measured and the calculated dose were within ±3%, whereas 93.3% of them between the predicted and the calculated dose were within ±3%. As for planar dose differences, the gamma passing rates between the calculated and the predicted dose were higher than those between the calculated and the measured dose. Comparison and statistical analysis revealed a correlation between the predicted and the measured dose with regard to both point dose and planar dose differences. We concluded that the prediction-based approach is an accurate substitute for the conventional measurement-based approach in IMRT QA for the pelvic region. Our novel approach will help medical physicists save time on IMRT QA.
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Affiliation(s)
- Keita Kurosu
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan Department of Radiology, Osaka University Hospital, Osaka, 565-0871, Japan
| | - Iori Sumida
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Hirokazu Mizuno
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Yuki Otani
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Michio Oda
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan Department of Radiology, Osaka University Hospital, Osaka, 565-0871, Japan
| | - Fumiaki Isohashi
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Yuji Seo
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Osamu Suzuki
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Kazuhiko Ogawa
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
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